The past perfect tense in English is composed of two parts: the past tense of the verb to have (had) + the past participle of the main verb. For example, "We had decided…," "She had given…," or, "I hadn't asked…"

The past perfectrefers to a time earlier than before now. It is used to make it clear that one event happened before another in the past. For example, "John had gone out when I arrived in the office," or, "He was very tired because he hadn't slept well."

Just is used with the past perfectto refer to an event that was only a short time earlier than before now. For instance, "She had just left the room when the police arrived," or, "We had just started the picnic when it began to rain."